The invention relates most immediately to a host-torch body or handle construction which will enable a gas metal arc welding (GMAW) shop to accommodate and serve the relatively elevated gas-flow requirements of a gas-constricted arc nozzle, on the basis of selective interchangeability with respect to one or more other arc-welding processes for which the shop may or should be equipped.
Gas-constricted electric-arc nozzles of the character indicated may be as shown and described in pending patent applications, Ser. No. 824,525, filed Jan. 31, 1986, and Ser. No. 850,690, filed Apr. 11, 1986. And in another patent application, Ser. No. 850,626, filed Apr. 11, 1986, an adapter device is described whereby supporting apparatus which exists in gas metal arc welding (GMAW) shops throughout the world may be quickly and selectively adapted to serve the relatively elevated gas-flow requirements of such gas-constricted electric-arc nozzles. It suffices here to state that the GMAW supporting apparatus which remains usable to serve the gas-constricted electric-arc nozzle includes the existing electric-power supply for operation of the arc, existing wire-feeding mechanism in the event of nozzle use with consumable electrode material, existing flexible hose (1) for supplying electric current to a host-torch body dedicated to a particular nozzle configuration and (2) for delivering a flow of shielding gas to the torch body and its nozzle, and an existing gas-flow on/off control means in the form of a solenoid valve.
The only change necessary to adapt this existing apparatus to serve the gas-constricted arc nozzle is to substitute a gas supply of substantially greater capacity for the charged-gas cylinder that is customarily hose-connected to the solenoid; and the substitution is easily effected if the adapter includes a main valve for on/off admission of shop air via a separate flexible hose to the nozzle, while the hose which serves the solenoid valve is disconnected from the gas cylinder and, instead, is connected to the control port of the adapter, thus converting the existing solenoid valve from its original main-valve function to a new pilot-valve function for controlling the main-valve function of the adapter. It suffices here to note that, having made this control connection to the adapter, an opening of the solenoid valve vents the pressure which would otherwise close the main valve of the adapter, with resultant admission of shop air to the torch nozzle; on the other hand, a closing of the solenoid allows a bleed of shop-air pressure to close the main valve of the adapter, with resultant cut-off of shop-air delivery to the torch nozzle.
The conventional host-torch body for a GMAW system is substantially dedicated to essentially a single welding application, the variety of specific application being largely a function of interchangeability of one electrode tip for another, such a change being necessitated by electrode damage attributable to burnback, dross accumulation, or other factors. But now that it appears that existing GMAW equipment can be simply and quickly adapted to serve the additional use of the gas-constricted arc nozzle, a need exists for a host-torch body construction which will enable quick and effective change of nozzle configuration to best serve a prospective welding application.